1. Field of the Invention
This invention relates to a method and to an apparatus for balancing a spindle or other rotating machinery and, more particularly, to an improved tool holder including a balancer assembly portion which provides enhanced balancer capabilities over that provided by prior balancer assemblies.
2. Background of the Invention
A typical machine tool assembly includes a rotating spindle or other type of movable member which is normally adapted to selectively and removable receive and/or to be removably but securely coupled to a tool holder. The tool holder is itself adapted to removably and securely receive a tool in a manner which allows the tool to move in response to the movement of the spindle. As the tool moves it performs some desired operation upon some surface or body often referred to as a xe2x80x9cworkpiecexe2x80x9d. The machine tool assembly therefore normally includes the cooperative combination of the tool, the tool holder, and the rotating or moving spindle which form or xe2x80x9cmachinexe2x80x9d the work piece into a xe2x80x9cfinished productxe2x80x9d having a desired shape and configuration.
Typically, these machine tool assemblies experience a certain amount of unbalance and associated unbalance induced vibrations caused by the unbalance created by the wear and tear experienced by the tool and/or by a failure or xe2x80x9cloosenessxe2x80x9d in the coupling between the tool holder and the tool and/or between the tool holder and the spindle.
These unbalance type vibrations oftentimes cause the tool to inaccurately perform the desired task (e.g. the desired cuts within the workpiece are not of a uniform and desired depth), significantly decrease the overall tool life, and cause the production of a finished product which must be discarded resulting in a concomitant and undesired waste of resources. Accordingly, it is highly desirable to maintain the tool, tool holder, and spindle in a state of relative balance, thereby increasing the overall working life of the tool, increasing the overall accuracy with which the tool performs its work, increasing the overall operating life of the balancer assembly and consistently creating finished products of a desired shape and size.
The Applicants have previously discovered and have previously patented a new and useful balancer assembly using several rotors which are selectively moved by means of at least one electromagnetic signal which selectively emanates and/or is generated from a driver. This electromagnetic balancer assembly is described and claimed within U.S. Pat. No. 5,757,662 (the ""662 patent); filed on Nov. 29, 1994; issued on May 26, 1998; and assigned to these Applicant""s Assignee. The ""662 patent is fully and completely incorporated herein by reference, word for word and paragraph for paragraph.
While the balancer assembly described and claimed within the ""662 patent provides for a highly desirable and highly efficient unbalance compensation, Applicants have recently discovered that this balancer assembly offers even improved and greater unbalance compensation performance if adapted for use upon and/or as an integral part of a tool holder, thereby providing a tool holder with an integrally formed balancer assembly and/or a balancer assembly removably placed upon the tool holder. In fact, Applicants have discovered that the placement of the balancer upon the tool holder provides for increased effectiveness of vibration balance and control since the balance compensating element is now positioned in relatively close proximity to the actual source of vibration (e.g. the tool and the tool holder). Moreover, Applicants have found that the placement of the balancer upon the tool holder provides for a more accurate overall balancing condition since the balance compensation is achieved very close to the unbalance condition. Heretobefore, prior unbalance compensators could not achieve these highly desirable results since these prior unbalance compensators were not capable of being adapted for placement upon the tool holders due to their size, geometric configuration, and/or their employed unbalance compensation methodology.
Accordingly it is a principal object of the present invention to provide a tool holder having balancer portion which is selectively adapted to provide desired and improved unbalance compensation for the tool, tool holder, and for the entire balancer assembly and which allows the amount of vibration to be accurately measured and which further improves the overall accuracy of the unbalance compensation which is selectively provided.
It is therefore a primary object of this invention to provide an improved method and apparatus for selectively and relatively quickly and efficiently balancing rotating machine apparatuses and other similar types of devices.
It is another object of this invention to provide an improved method and an apparatus which corrects a relatively large amount of vibration which is caused by rotating unbalance.
It is yet another object of the invention to provide an unbalance compensator which is adapted to be disposed upon and/or integrally formed within a machine tool holder and which is further adapted to selectively provide desired unbalance compensation.
According to a first aspect of the present invention a tool holder of the type adapted for use upon a spindle is provided. According to this first aspect of the present invention, the tool holder includes a generally elongated body having a tool reception portion which is adapted to removably receive a tool and an opposed spindle portion which is adapted to removably attach to a spindle; and a balancer which is adapted to selectively balance the tool and tool holder.
According to yet another aspect of the present invention a method of unbalance compensation is provided. The method includes the steps of providing a tool holder; providing a tool; placing the tool into the tool holder; providing a balancer; placing the balancer upon the tool holder; providing a spindle; placing the tool holder onto the spindle; rotating the spindle; measuring an amount of vibration caused by unbalance of the tool; and balancing the tool as the spindle is rotating, thereby providing compensation for at least a portion of the measured amount of rotating unbalance.
Further objects, features, and advantages of the present invention will become apparent from a consideration of the following description and the following subjoined claims when taken in conjunction with the attached drawings.